A new Computational Fluid Dynamic tool, based on OpenFOAM, was implemented to reproduce a physical wave tank for offshore applications. The code has new boundary conditions for deep water wave generation, a new turbulent model and a new numerical restraint to represent realistic mooring lines in OpenFOAM. A real study case application of this tool is shown hereby: a preliminary analysis of a floating wind turbine offshore Mazara del Vallo, (Italy). The application demonstrated the usefulness and capability of the model. Moreover, with active absorption, the dimension of the numerical domain, computational costs and time of the simulations are reduced.
The numerical simulation of free surface flow problems is a challenging topic (Gaeta et al. 2015), furthermore modelling the presence of a moving structure, however, it has been of considerable importance to the development of offshore structures. Several types of models are commonly seen in numerical simulation of the non-linear waves and wave-structure interaction (Antonini et al. 2016). Hereby, a new tool based on OpenFOAM was implemented in order to analyse floating offshore structures hit by waves and currents. OpenFOAM version 2.3.0 was adopted in this work. In particular, the new features of the tool improved the generation and absorption of waves and currents already implemented in IHFOAM (Higuera et al. 2013), through new boundary conditions and turbulence model, so the code can correctly simulate deep water conditions too (Paci, 2018). The implementation of a new boundary condition to actively absorb in deep water conditions was done by the changing the formula of the correction of the velocity in both inlet and outlet patches. As for shallow water, it was calculated with shallow water approximation, now, for deep water, it is with the corresponding approximation. That velocity equation contains the celerity expression:
(equation)
As for shallow water, it was calculated with shallow water approximation, now, for deep water, it is with the corresponding approximation:
(equation)
(equation)
